Table 3. Cox Regression for Time to Relapse: Multivariate Model Examining Variables Associated With Hazard of Relapse to Major Depression.
| Variablea | df | p | Max. log likelihood | Change in max. log likelihood | |
|---|---|---|---|---|---|
| Note. Max. = Maximum; CTQ = Childhood Trauma Questionnaire; HAMD = Hamilton Rating Scale for Depression; CI = confidence interval; MBCT = mindfulness-based cognitive therapy; CPE = cognitive psychological education; TAU = treatment as usual; B = Bangor. | |||||
| a Analysis of 255 participants with follow-up data. Other variables considered during the stepwise process but not included in the final model were gender; stratifying variables at baseline, namely, cohort, suicidality, and current antidepressant use; and moderators at baseline, namely, episodes of major depression, Beck Depression Inventory, Beck Hopelessness Scale, and Beck Scale for Suicide Ideation. b As the two contrasts of interest (MBCT vs. CPE and MBCT vs. TAU) are not orthogonal, we derived these rows by rerunning the model with group contrasts MBCT vs. TAU and (MBCT or TAU) vs. CPE (not shown). | |||||
| Block 0: Initial log likelihood | 1304.26 | ||||
| Block 1: Group | |||||
| 1. Group (forced entry) | 2 | .56 | 1303.08 | 1.17 | |
| Block 2: Stratification variables | |||||
| 2. Site | 1 | .01 | 1297.04 | 6.05 | |
| Block 3: Modifier variables | |||||
| 3. CTQ | 1 | .01 | 1290.43 | 6.60 | |
| 4. HAMD | .02 | 1285.86 | 4.57 | ||
| Block 4: Interactions | |||||
| 5. CTQ × Group | 2 | .00 | 1272.43 | 13.44 | |
| 6. Site × Group | 2 | .04 | 1266.19 | 6.24 | |
| Final model | 9 | <.01 | 1266.19 | 38.07 | |
| Components of final model | Wald | df | p | Hazard ratio (HR) | 95% CI for HR |
| Group | 2.28 | 2 | .32 | ||
| MBCT vs. CPE | 0.34 | 1 | .56 | 0.88 | [0.57, 1.34] |
| (MBCT or CPE) vs. TAU | 1.98 | 1 | .16 | 0.73 | [0.47, 1.13] |
| MBCT vs. TAUb | 2.26 | (1) | .13 | 0.68 | [0.42, 1.12] |
| Site | 3.43 | 1 | .06 | 1.43 | [0.97, 2.09] |
| CTQ | 6.42 | 1 | .01 | 1.01 | [1.00, 1.02] |
| HAMD | 5.31 | 1 | .02 | 1.06 | [1.00, 1.11] |
| CTQ × Group | 13.56 | 2 | .00 | ||
| CTQ × (MBCT vs. CPE) | 9.02 | 1 | .00 | 0.96 | [0.94, 0.98] |
| CTQ × (MBCT or CPE) vs. TAU | 7.24 | 1 | .00 | 0.97 | [0.95, 0.99] |
| CTQ × (MBCT vs. TAU)b | 12.46 | (1) | <.01 | 0.95 | [0.92, 0.97] |
| Site (B) × Group | 6.12 | 2 | .04 | ||
| Site × (MBCT vs. CPE) | 6.06 | 1 | .01 | 2.76 | [1.23, 6.21] |
| Site × (MBCT or CPE) vs. TAU | 0.11 | 1 | .74 | 1.15 | [0.49, 2.71] |
| Site × (MBCT vs. TAU)b | 1.79 | (1) | .18 | 1.92 | [0.73, 5.01] |